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One two-dimensional Fe-based metal−organic framework (FeSC1) and one one-dimensional coordination polymer (FeSC2) have been solvothermally prepared through the reaction among FeSO 4 •7H 2 O, the tripodal ligand 4,4′,4″-striazine-2,4,6-triyl-tribenzoate (H 3 TATB), and flexible secondary building blocks p/m-bis((1H-imidazole-1-yl)methyl)benzene (bib). Given that their abundant interlayer spaces and different coordination modes, two compounds have been employed as battery-type electrodes to understand how void space and different coordination modes affect their performances in three-electrode electrochemical systems. Both materials exhibit outstanding but different electrochemical performances (including distinct capacities and charge-transfer abilities) under three-electrode configurations, where the charge storage for each electrode material is mainly dominated by the diffusion-controlled section (i ∝ v 0.5 ) through power-law equations. Additionally, the partial phase transformations to more stable FeOOH are also detected in the longterm cycling loops. After coupling with the capacitive carbon-based electrode to assemble into the semi-solid-state battery− supercapacitor-hybrid (sss-BSH) devices, the sss-FeSC1//AC BSH device delivers excellent capacitance, superior energy and power density, and longstanding endurance as well as the potential practical property.

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Narrowing the capacitance gap between the positive and negative electrodes for the enhancement of the energy densities of battery–supercapacitor hybrid (BSH) devices is urgent and very important. Herein, a new strategy to synchronously improve the positive–negative system and reduce the capacitance discrepancies between two electrodes through the utilization of the same MOF-based precursors ([Ni­(ATA)2(H2O)2]­(H2O)3) has been proposed. Nickel/nitrogen codoped carbon (Ni@NC) materials, serving as positive electrodes, deliver battery-type behavior with the enhancement of capacities, which are even superior to those of pristine carbon-based materials with large surface areas. Meanwhile, HCl-treated Ni@NC materials (named A-Ni@NC) are employed as negative electrodes within the potential window of −1 to 0 V and exhibit higher capacitances than that of the commercial activated carbon. With Ni@NC and A-Ni@NC as positive and negative electrodes in BSH devices, the as-fabricated cells display higher capacities and energy densities, more excellent cycling stability, and far superior capacity retention in comparison with those of Ni@NC//AC cells. These results clearly confirm that our strategy is successful and effective.

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